Tri-wire cables?

I just bought a pair of Hyperion 938's which are tri-wireable. Aside from Kimber (wildly expensive), who makes tri-wired cables?
To my understanding bi-wire or tri-wire speakers are best when ran with seperate cables 2 for bi 3 for tri. But I could be wrong Im sure the other guys will set me straight.
Why not use three individual runs of whatever you like?

Linn makes tri-wire cable.
I have made multiple pair from various cables for my Alon speakers, which have tri-wire binding posts. I am currently using DH Labs with two single T-14's for mid and high frequencies, and one Q-10 for low frequencies to each speaker. I have some tri-wire Jon Risch CC89259 using the quad version for LF, and I have terminated Alon's Black Orpheus, Cardas bulk wire and others. You didn't mention the length you need, or your price range. I usually try to terminate the three cables together at the amp end with a single spade (there are only a few big enough for all that wire). If you are trying to go with a factory terminated cable, a good way to do it is to get a biwired set with a single spade at the amp end for MF and HF, then a separate single run with a banana at the amp end for the LF. If your amp has typical binding posts with a back hole made for bananas, you can clamp the spade for the bi-wire pair, then use the banana into the same binding post for the LF pair.
Linn K-600 or Jenna Labs.
Alon also makes tri-wire cables, called Black Orpheus, that are quite good sounding and reasonably priced. They come up on the used market from time to time, and they're not that expensive new either.
Ridge Street Audio. Separate runs for each + & -.